This paper examines how the lighting of roads in the UK might be changed so as to preserve the benefits while minimising energy consumption. It is divided into four sections, these being changes in technology, changes in patterns of use, changes in standards and contracts and changes in the basis of design. Useful changes in technology and patterns of use are available now, but their use will raise the question as to whether or not environmental considerations can override conventional financial constraints. Changes in standards and the basis of design are much more long term. Comparisons of road lighting standards used in different countries show significant differences that deserve examination. As for the basis of design, consideration of the importance of light to fatal and personal injury accidents of different types suggests that road lighting should be concentrated where pedestrians are common, not where speeds are highest. Ultimately, considering carefully what problem road lighting is intended to solve and whether or not road lighting is the best answer is the key to minimising the energy consumption of road lighting without diminishing road safety.

After dark, road lighting should enhance the visual component of pedestriansâ interpersonal judgements such as evaluating the intent of others. Investigation of lighting effects requires better understanding of the nature of this task as expressed by the typical distance at which the judgement is made (and hence visual size) and the duration of observation, which in past studies have been arbitrary. Better understanding will help with interpretation of the significance of lighting characteristics such as illuminance and light spectrum. Conclusions of comfort distance in past studies are not consistent and hence this article presents new data determined using eye-tracking. We propose that further work on interpersonal judgements should examine the effects of lighting at a distance of 15&#8201;m with an observation duration of 500&#8201;ms.

The effect of spectrum on the visibility of roadway lighting targets was investigated. The experiment focused on the relation between average visibility ratings and small target visibility (STV) under installations that employed LED and HPS light sources. Achromatic targets were more visible under LEDs illumination conditions than under HPS illumination conditions. The results also suggest that the visibility of colored objects on the road was better under LEDs illumination conditions in comparison to HPS. The results cannot be generalized to all LED light sources, but are likely indicative of LEDs with similar spectral power distributions (SPDs). Relative visibility under source types with different SPDs, and which provide different luminance distributions, should merit consideration when selecting a light source for roadway lighting.

The paper considers the justification for the application of light-emitting diode (LED) technology to urban lighting. The results suggest that LEDs are convenient for architectural lighting and deserve to be considered for use in ambient lighting. The recently developed Commission Internationale de lâEclairage (CIE) mesopic system enabled the inclusion of mesopic effects into a comprehensive techno-economic analysis, which dealt with efficiency, maintenance and financial aspects of the use of LEDs in street and roadway lighting. It is concluded that the average energy savings when using LED instead of high-pressure sodium (HPS) luminaires amount to 19â26% for single-sided, staggered and opposite layouts, although they are frequently negligible if mesopic effects are not included. The total costs of the LED lighting solutions, even including mesopic effects, are 1.36 to 6.44 times higher than those of the comparable HPS lighting solutions. Therefore, LEDs are questionable for street and roadway lighting.

Lighting is essential for sight, human health and well-being, emerging the need for assessing exterior lighting to better understand how far public is satisfied about exterior lighting. Exterior lighting was assessed in five major roads of the capital city of Tirana, Albania, in November 2017. Security, obstacle detection and visibility were evaluated using questionnaires for road lighting. The approximately 87 and 60 percent of respondents, respectively, were not able to detect a pavement obstacle after-dark and to distinguish a

familiar face at a distance of 5 m and 10 m along roads. Road lighting after-dark was unsatisfactory to 60 percent of respondents. These findings identified road lighting could be inadequate for users, requiring further investigation and new data collection of road lighting in neighborhoods of Tirana.